Washington — Mitt Romney will go after President Obama’s health-care reform Thursday, in the first major speech of his presumed presidential campaign.

But all signs point to gentle treatment of the health-care reform he instituted in his own state of Massachusetts, when he was governor from 2003 to 2007. Mr. Obama often praises Mr. Romney’s health reform as the model for the national version, including a mandate that requires individuals to purchase insurance.

Perhaps more than any other aspect of his candidacy, Romney’s health reform is a major liability among many Republican voters. Romney polls at or near the top of the still-forming GOP field, but only in the high teens.

In an address at the University of Michigan in Ann Arbor, Romney is expected to call for repeal of “ObamaCare” and then lay out a five-point plan for a replacement. On Wednesday, he previewed his proposal in an op-ed at USAToday.com.

“If I am elected president, I will issue on my first day in office an executive order paving the way for waivers from ObamaCare for all 50 states,” Romney wrote. “Subsequently, I will call on Congress to fully repeal ObamaCare.”

His five-step replacement reform calls for the following:

“Give states the responsibility, flexibility and resources to care for citizens who are poor, uninsured, or chronically ill.” Romney suggests that “some states might pass a plan like the one we did in Massachusetts, while others will choose an altogether different route.” It is the only reference to the Massachusetts reform, which has resulted in more than 97 percent of state residents carrying health coverage. Notably, he neither refutes nor defends it.

Provide a tax deduction to those who purchase their own insurance, just as those who get insurance via their employer are subsidized.

Reform federal regulation of health care. Measures include barring insurers from rejecting customers with preexisting conditions, as long as they have had continuous coverage for a specified period, and allowing customers to purchase insurance across state lines.

Medical liability reform, including a cap on noneconomic damages in malpractice litigation.

Make health care more like a consumer market, through expanded use of health savings accounts.

“What I would tell him to do is distance himself from RomneyCare,” says Matt Kibbe, president and CEO of FreedomWorks, which advises tea party groups.

Mr. Kibbe says he knows Romney won’t do this, but he wishes Romney would say, “The biggest regret I have is imposing an individual mandate, because it’s completely inconsistent with the tenets of our party and [its] philosophy.”

Reporters and interest groups scouring news archives have found multiple examples of Romney touting the individual mandate – not federally, but at the state level. The Washington Post dug up this one: On NBC’s “Meet the Press” on Dec. 16, 2007, Romney said: “I think it’s a good model for other states. Maybe not every state, but most.”

“I think it’s a terrific idea,” Romney said. “I think you’re going to find when it’s all said and done, after all these states that are the laboratories of democracy, get their chance to try their own plans, but those who follow the path that we pursued will find it’s the best path, and we’ll end up with a nation that’s taken a mandate approach.”